The present invention relates to fuel pre-heater apparatus for exchanging engine heat withdrawn from an internal combustion engine system into heat for pre-heating fuel for subsequent use in the internal combustion engine and regulating water flow control along the heat transfer surface of the pre-heater apparatus. The apparatus is capable of use in combination with any liquid cooled internal combustion engine such as gasoline, gasohol and diesel engines, and the like, for automobiles and trucks so that the fuel being processed for use by an internal combustion engine such as it being processed by a carburetor or the like, passes through a space for receiving heat that is withdrawn from the internal combustion engine cooling system. The invention also includes regulating the amount of heat transfer by appropriate use of a plastic pipe having apertures for selectively passing a heated turbulent media into engagement with a heat transfer surface and can be replaced for achieving various quantities of heat transfer for the advantage of fuel saving and efficiency in mileage per gallon of fuel.